Piston



K. D. HOLLAND.

PlSTON.'

APPLICATION FILED APR.28. 1919.

Eatensed June 2% 1922.

I 17201 228 07 4a; w d9. 46m? fi Fill A ollcation filed April 2%;

To all iii/2cm it may armor r):

lie it known that l. Kins; l). HOLLAND, a. citizen of the United States, residing at Qhioago, in. the county of Cook and State of lllinois, have invented certain new and useful Improvements in Pistons of which the following is u. specification.

In the operation oi internal combustion engines one very common source of trouble is the passage of oil which is employed for lubricating the piston to reduce its friction in the cylinder from the crank case into the combustion chamber, where it is carbonized and deposited on the cylinder wells and valves and the spark plug, and materially injures and reduces the eliiciency oi the engine, or at times entirely prevents the parts of the engine from functioning. The object oi my invention is to provide means for preventing this passage of oil into the combustion chamber, thus preventing the formation oi curbon and obviating the destructive and injurious effects thereby produced upon the engine. To this end I have devised and invented the novel form of piston shown in the accompanying drawings and which is hereinafter described in detail. the essential elements oi m; invention being pointed out in the appended claims.

Figure 1 oi the drawing is a central vertirul section Oi ii trunk piston embodying my invention and of a form adapted for use in ordinary gasoline automobile engines; Fig. 12 is :1 section of the same at right angles to the plane of Fig. 1; Fig. 3 is a horizontal se tion on the broken line 3-4.. oi Fig. 2. the lett huntl side of said tipurc showing in cle- 'ution parts above the plane of the section and he right-hand side the parts below. us iiulicuted by the airows respectively shown at the left and right hand ends of the broken section line; and Fig. l is ii central vertical section corresponding to Fig. 2, but illustrating u modified form l my invention The same reference characters indicate the some parts in all the figures of the drawing.

lnusinuch us the form of the combustion chamber and uriwingen'ient oi" the valves of engine. and also the specific construction and arrangement of the crank case members may vary widely. l hive deemed it umcrcsszir i' to illustrzii'ic such parts of the 4=ii;, inr.- it will br- Ill1!lll l l. how'rviug in explaining the operation oi' my improve l ion. that the cylinder well i of the engineu; (ftllbl llli'ftl shove the piston to form at coinbustion chamber and that otters recent.

in accordance with common practice the cylinder well is lubricat-ed by a proper splash device which acts to dash the lubricating oil upon it plentifully from below.

My improved piston 2, us in the case of ordinary pistons, is formed to: lit the cylinder as accurately and closely as is possible consistent with freedom. of reciprocating move ment therein, and is equipped with piston rings 3 of any suitable or known form of constructioin the piston illustrated being provided with three rings above the plane of the cross-pin and two in the lower part of the skir though the number and arrang ment may be varied. About midway of the skirt of the piston the piston wall formed with deep inwardly and downwardly Q};- tending peripheral bend or corrugation 4 which is formed continuous with the diametricul. inwardly extending bosses 5 forming the bearings for the cross pin of connecting rod. As shown, the bottom portion of the external groove formed on the piston by this bend in the piston well constitutes an annular cup 6 into which oil from the cylinder well may flow and from which it may drain back into the crank case through the drain ports '4', six of which are provided in the piston illustrated. The upper portion of the peripheral inward bend 4 is iorined with a like number of relief ports 8 connecting the crank case space and the annular oil-collecting chamber formed by the bend and the cylinder wall.

lin ordinary pistons (as in my improved pistons) there is necessarily e slight space between the cylinder wall and the piston, and here is also necessarily a. slight space at the top and bottom of each piston ring and at its back since the rings must be free to spring outwardly against the cylinder wall.

The bottom faces of the rings and the proximate feces of the rings grooves are ordinarily finished to make a. close (it, and Lllll' ing the compression, power and exhaust strokes the prepouderant pressure is on the top or face of the piston and whatever pressure escapes around the bottom face of the piston rings tends to drive the oil which fills the space between the piston and cylinder and in the groove back towards the. crank case. ()n the suction or charging stroke, however, the. atmospheric pressure in the crank case. proponderntes over the reduced pressure in the combustion chamber and the result is that the film of oil between the piston and cylinder wall and the oil on the lower part of the cylinder wall against which the piston is moving is drawn up' wardly towards and into the combustion chamber. This is particularly true in cold weather, before a normal working temperature in the engine has been reached and before the parts have expanded to their normal working dimensions, and the superfluous clearance or leakage is such that a considerable quantity of lubricating oil is apt to be drawn into the mmbustibn chamber and materiall Y affect t is operation of the engine and produce the injurious results hereinbefore mentioned.

With this explanation and understanding of the defect in ordinary pistons which the present invention is intended to obviate, the function of the annular oil-collecting chamher around the piston will readily be understood. As the piston descends on its suction stroke its lower edge will scrape a wave of oil in front of its lower edge, but the preponderant air pressure in the crank case will pass through the relief ports 8 (and in most cases in part also through the drain ports 7, which are of large capacity), and there will therefore be no tendency to draw this oil up pastthe bottom of the skirt of the piston. Snob oil as adheres to the parts and reaches the oil collecting chamber is free to drain back, and only a sufficient quantity of oil to properly lubricate the piston reaches its upper portion. The rings below the oil-collecting chamber, it will be observed, have no function in preventing the escape of fluid pressure in either direction, and act merely as scrapers to remove superiluous oil from the cylinder wall, and to cause even wear of the cylinder wall. The relief ports 8 serve to assure at all times the relief of preponderant air pressure, even though the lower part of the oil-collecting chamber should fill so as to cover the drain ports 7, although the latter should preferarness ably be of such size as to permit such oil as roaches them to drain through without closing them. i

In Fig. 4 l. have illustrated a modified form of my invention in which the oil-cob l'ccting groove or channel 10 is formed be low the level of the cross-pin of the piston. The piston wall is formed with drain ports 11 and relief ports 12 similar to the piston first described and the functions of the corresponding parts are the same.

I claim:

1. in combination with the cylinder of an internal combustion engine, a piston having a head formed with a cylindrical ring-carrying portion, and having also an inwardly curved intermediate wall which is connected at the top with the bottom of said cylindrical portion and which is cupped at the bottom to provide an external annular oil collecting chamber, and having also a cylindrical skirt continuous at the top with the periphery of the cupped bottom of said intermediate wall, said cupped bottom having orts of large capacity arranged to drain into the crank case space.

2. In combination with the cylinder of an internal combustion engine, a piston formed with a cylindrical ring-carrying head portion and with an intermediate portion consisting of an inwardly curved wall arranged to provide an external annular oil-collecting chamber and with a cylindrical skirt below said curved intermediate portion, such curved intermediate portion having drain ports adjacent its bottom arranged to drain into the crank case space and also having relief ports above said drain ports.

3. in combination with the cylinder of an internal combustion engine, a piston. havin its skirt formed with a peripheral inward bend forming an oil-collecting channel and bosses continuous with said bend forming a cross-pin bearing, said channel having openings into the crank case space.

' KIRK D. HOLLAND. 

